JPH073220A - Adhesive sheet for decoration - Google Patents

Abstract

PURPOSE:To provide an adhesive sheet not causing a whitening phenomenon and a color-fading phenomenon, excellent in weatherability, and used for decoration. CONSTITUTION:An adhesive for decoration is constituted by laminating a surface layer comprising zinc oxide fine particles and polyvinyl fluoride, polyvinylidene fluoride, vinylidene fluoride copolymer or their acrylic modified products or their mixture with an acrylic resin to one surface of a resin sheet substrate, and an adhesive agent layer to the other surface.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a decorative pressure-sensitive adhesive sheet having excellent weather resistance.

[0002]

2. Description of the Related Art Conventionally, a decorative pressure-sensitive adhesive sheet is known in which a pressure-sensitive adhesive layer is laminated on one surface of a substrate made of an opaque, transparent or translucent resin sheet mainly made of polyvinyl chloride containing a pigment. ing. This decorative adhesive sheet
It is used by applying an adhesive layer to the material to be decorated and exerting a decorative effect by the color and pattern of the surface side of the above resin sheet. In recent years, instead of painting, it is used in the field of displays such as advertisements and signboards. It is used in fleet marking fields such as vehicle decoration.

Since these are used outdoors, there are problems such as deterioration and discoloration of the resin sheet due to ultraviolet rays contained in sunlight. In order to solve this problem and impart weather resistance, there were those in which an organic UV absorber such as benzophenone was mixed in the resin sheet, and those in which the sheet itself was made of a fluororesin such as polytetrafluoroethylene.

[0004]

However, in the above-mentioned products, although the problem of discoloration is improved, there is a problem in that the surface of the resin sheet is deteriorated and the surface of the resin sheet is whitened (chalking).

In the above-mentioned products, the resin itself is less deteriorated by ultraviolet rays, but the fluororesin has a problem that it cannot prevent deterioration of the pigment and is discolored due to its high ultraviolet transmittance. In order to solve this, it was also attempted to blend an organic UV absorber, but the solubility of the UV absorber in the fluororesin is low, and the heat resistance of the UV absorber is lower than the molding temperature of the fluororesin. There were restrictions such as low, so it was not an effective means. Further, since there are few pigments that are compatible with the fluororesin, there is a problem in that the color variation of the pressure-sensitive adhesive sheet for decoration is limited. The present invention solves the above problems, and an object of the present invention is to provide a pressure-sensitive adhesive sheet for decoration which is free from whitening phenomenon and discoloration and has excellent weather resistance.

[0006]

The surface layer of the decorative pressure-sensitive adhesive sheet of the present invention comprises polyvinyl fluoride, polyvinylidene fluoride, vinylidene fluoride copolymer, an acrylic modified product thereof or a mixture of these and an acrylic resin. , Zinc oxide fine particles.

The vinylidene fluoride copolymer used in the present invention is, for example, a vinylidene fluoride / tetrafluoroethylene copolymer, a vinylidene fluoride / tetrafluoroethylene / hexafluoropropylene copolymer, or vinylidene fluoride. And a copolymer of another monomer.

The acrylic modified product of polyvinyl fluoride, polyvinylidene fluoride and vinylidene fluoride copolymer used in the present invention means the main chain or side chain of polyvinyl fluoride, polyvinylidene fluoride and vinylidene fluoride copolymer. ,
(Meth) acrylic acid or (meth) acrylic acid ester is bound.

The acrylic resin used in the mixture of polyvinyl fluoride, polyvinylidene fluoride or vinylidene fluoride copolymer used in the present invention and acrylic resin is
For example, polymethylmethacrylate (eg Rohm &
Examples thereof include Paraloid A-21) manufactured by Hearth Japan, and a copolymer of methyl methacrylate (for example, Paraloid B-44 manufactured by Rohm & Haas Japan). Further, the mixing ratio of the acrylic resin is, in terms of weather resistance,
It is preferably 50% by weight or less with respect to the total amount of the mixture of polyvinyl fluoride, polyvinylidene fluoride or vinylidene fluoride copolymer and the acrylic resin.

Further, the polyvinyl fluoride, polyvinylidene fluoride, vinylidene fluoride copolymer and acrylic resin used in the present invention have a carboxyl group, a hydroxyl group, etc. in order to improve the adhesion to the resin sheet substrate. Those having a functional group can also be used.

The zinc oxide fine particles used in the present invention are characterized by
25m specific surface area ²/ G or more
preferable. As the specific surface area decreases, visible light absorption increases.
It is easy to impair the decorative effects such as the color and pattern of the resin sheet
Become. The average particle size is 1 μm in terms of visible light transmission.
The following are preferred. Polyvinyl fluoride used in the present invention
, Polyvinylidene fluoride, vinylidene fluoride copolymer
Or these acrylic modified products or these and acrylic
Resin component such as a mixture with resin and zinc oxide fine particles
The compounding ratio is such that 100 parts by weight of the resin component is zinc oxide.
2 to 20 parts by weight of fine particles are preferable. Amount of zinc oxide particles
As the amount decreases, the effect of imparting weather resistance decreases, and
Then, the absorption of visible light increases.

The thickness of the surface layer of the present invention is preferably 1 to 30 μm. When the thickness is thin, the effect of imparting weather resistance becomes small, and when it is thick, the decorative effect such as color and pattern of the resin sheet is impaired.

The material of the resin sheet base material used in the present invention is not particularly limited as long as it can be formed into a sheet or a film, but is preferably polyvinyl chloride, polyurethane, polyolefin, polyethylene terephthalate or the like. The synthetic resin of. Of these, polyvinyl chloride is preferable in terms of flexibility, weather resistance, and moldability. The polyvinyl chloride sheet is obtained, for example, by mixing a polyvinyl chloride with a pigment, a dye, a plasticizer, a stabilizer and the like, and casting or calendering. The thickness of this resin sheet is preferably 50 to 200 μm from the viewpoint of ease of use.

The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer used in the present invention includes, for example, rubber-based, urethane-based, silicon-based and acrylic-based pressure-sensitive adhesives, and acrylic resin is used from the viewpoint of adhesive strength and durability. The base is preferred. The thickness of the pressure-sensitive adhesive layer is preferably 20 to 50 μm in terms of adhesive strength to an adherend and ease of use.

An example of the method for producing the decorative pressure-sensitive adhesive sheet of the present invention is as follows. First, a solution of polyvinyl fluoride, polyvinylidene fluoride, a vinylidene fluoride copolymer, an acrylic modified product thereof, or a mixture of these and an acrylic resin. To prepare. As the solvent used for preparing the solution,
It is appropriately selected depending on the resin used and the layer forming means, and examples thereof include dimethylformamide, methyl ethyl ketone, butyl acetate, ethyl acetate, cyclohexanone and the like.

Next, the above zinc oxide fine particles are added to this solution and mixed using, for example, a stirrer, an ultrasonic disperser or the like. At this time, a surfactant may be added to improve the dispersion. As the surfactant, a cationic, anionic, amphoteric or nonionic surfactant is selected depending on the resin and solvent used. Particularly preferable are those having an acidic group such as carboxyl group and sulfonic acid group as a hydrophilic group in the surfactant molecule, those having a fluorine atom as a hydrophobic group, or those having both of them. A dispersion stabilizer may be added to prevent the dispersed zinc oxide fine particles from being separated. Examples of the dispersion stabilizer include silica (for example, Silysia 350 manufactured by Fuji Silysia Chemical Ltd.).

The obtained mixed liquid is applied to one surface of a resin sheet substrate and dried to form a surface layer. The coating method is not particularly limited, and examples thereof include coating with a gravure coater.

After the coated material is dried, an adhesive layer is then laminated on the other surface of the resin sheet substrate. A compounding composition material of the pressure-sensitive adhesive, for example, a general-purpose, such as toluene, xylene, ethyl acetate, dissolved in an organic solvent used industrially, to obtain a pressure-sensitive adhesive solution by dispersing, the pressure-sensitive adhesive solution to the substrate A pressure-sensitive adhesive layer is formed by applying and drying. The coating machine that can be used to form the pressure-sensitive adhesive layer is not particularly limited as long as it is used for ordinary pressure-sensitive adhesive solution coating, but preferably, the thickness can be accurately adjusted, Moreover, a knife coater, a comma coater, and a roll coater that can be applied with high productivity can be mentioned.

As a coating method, a pressure-sensitive adhesive solution is directly applied to the base material and dried, or a pressure-sensitive adhesive solution is once applied to a release paper and dried to form a pressure-sensitive adhesive layer and the base material Transfer method by pasting, etc.
It can be selected appropriately.

The decorative pressure-sensitive adhesive sheet thus produced is usually stored as a laminate in which a release sheet is attached to the pressure-sensitive adhesive layer surface, and the release sheet is peeled off from the pressure-sensitive adhesive layer surface before use.

[0021]

In the present invention, zinc oxide fine particles are used as an ultraviolet absorber, and the action of ultraviolet rays on the resin sheet base material is reduced, so that fading of the resin sheet base material is effectively prevented. In addition, zinc oxide fine particles absorb 1
It has a semi-permanent life due to its conversion to 00% heat. Further, by using the above-mentioned selected resin as the resin, deterioration of the resin due to ultraviolet rays does not occur, so that the surface layer exhibits semi-permanent weather resistance. Since the surface layer of the present invention has a large weather resistance due to the durability of the zinc oxide fine particles acting as the ultraviolet absorber and the durability of the resin, the weather resistance of the resin sheet is remarkably improved.

[0022]

【Example】

(Example) FIG. 1 is an enlarged sectional view of a decorative pressure-sensitive adhesive sheet 1 of the present invention, in which a surface layer 12 is laminated on one surface of a resin sheet substrate 11 and a pressure-sensitive adhesive layer 13 is laminated on the other surface. The above-mentioned pressure-sensitive adhesive sheet for decoration was manufactured as follows. A blue soft vinyl chloride sheet 11 having a thickness of 50 μm, which was produced by a casting method, and an acrylic pressure-sensitive adhesive layer 13 laminated on it (Tak Paint TP-05, manufactured by Sekisui Chemical Co., Ltd.) was prepared.

A zinc oxide particle-dispersed resin solution for forming a surface layer was prepared as follows. Dissolved in a solvent consisting of 70 parts by weight of ethyl acetate and 25 parts by weight of cyclohexanone,
Tertiary copolymer of ethylene difluoride, ethylene tetrafluoride and propylene hexafluoride (manufactured by Atochem, KYNAR-
79 parts by weight of a 25% by weight solution of ADS) and 40% by weight of a copolymer of methyl methacrylate and ethyl acrylate (Paraloid B-44 manufactured by Rohm & Haas Japan).
A resin solution was prepared by mixing 21 parts by weight of a toluene solution. 320 parts by weight of this resin solution has a specific surface area of 50 m ² /
10 parts by weight of zinc oxide fine particles (manufactured by Sakai Chemical Industry Co., Ltd.) of g were added, stirred and dispersed by an ultrasonic disperser to obtain a zinc oxide fine particle dispersed resin solution.

The above zinc oxide fine particle-dispersed resin solution is applied on the surface of the resin sheet 11 by using a bar coater so that the thickness after drying becomes 20 μm, dried at 70 ° C. for 30 minutes, and The decorative pressure-sensitive adhesive sheet 1 of the invention was obtained. Furthermore, a release paper 14 was attached to the surface of the adhesive layer 13.

The obtained decorative pressure-sensitive adhesive sheet 1 was used as a release paper 1
After peeling off No. 4, it was set on a sunshine weatherometer, and the relationship between irradiation time and surface gloss retention was examined as weather resistance evaluation. The gloss retention rate was measured by a gloss meter according to JIS K-7105. The results are shown in Table 1 and FIG.

(Comparative Example) A blue soft vinyl chloride sheet 11 having a thickness of 50 μm and manufactured by a casting method, and an acrylic pressure-sensitive adhesive layer 13 laminated thereon (manufactured by Sekisui Chemical Co., Ltd., used in Examples). Tuck Paint TP-05) was set on a sunshine weatherometer as it was, and the weather resistance was evaluated in the same manner as in Examples. The results are shown in Table 1 and FIG.

[0027]

[Table 1]

[0028]

The constitution of the pressure-sensitive adhesive sheet for decoration of the present invention is as described above, the sheet surface is not whitened, and it is not discolored, and is excellent in weather resistance, and is an outdoor marking material. Can be suitably used as.

[Brief description of drawings]

FIG. 1 is an enlarged cross-sectional view showing a decorative pressure-sensitive adhesive sheet of the present invention.

FIG. 2 is a graph showing the results of weather resistance evaluation of the decorative pressure-sensitive adhesive sheets of Examples and Comparative Examples.

[Explanation of symbols]

 1 Adhesive Sheet for Decoration 11 Resin Sheet Base Material 12 Surface Layer 13 Adhesive Layer 14 Release Paper

Claims (1)

[Claims] 1. A surface comprising a zinc oxide fine particle on one surface of a resin sheet substrate, polyvinyl fluoride, polyvinylidene fluoride, a vinylidene fluoride copolymer, an acrylic modified product thereof or a mixture of these with an acrylic resin. A decorative pressure-sensitive adhesive sheet, comprising a layer and a pressure-sensitive adhesive layer laminated on the other surface.